If you've spent any time in the trying to conceive corner of the internet, you've probably seen CoQ10 mentioned in the same breath as prenatal vitamins and ovulation strips. Maybe your fertility clinic brought it up in passing. Maybe a friend swears by it. Maybe you added it to your basket because everyone else seemed to have already made up their mind.

You're not imagining it: there is real, peer reviewed research behind CoQ10 and reproductive health. But there is also a lot of marketing noise dressed up as science, and the two don't always agree with each other. If you've found yourself squinting at a supplement label at 11pm trying to work out whether it's actually backed by anything, or whether it's just well designed packaging, you are far from alone.

So here is the promise of this article. We are going to walk through what CoQ10 actually does in your body, what the current fertility research shows and where it falls short, how much people typically take, and how it fits alongside other nutrients like myo-inositol, zinc, and folate. No hype, no guarantees, just the evidence as it currently stands.

The short version: CoQ10 is a compound your cells use to make energy, and it is especially important in mitochondria-dense cells like eggs. Early research, including a landmark 2015 mouse study and several small human trials in women undergoing IVF, suggests CoQ10 supplementation before treatment may support egg quality and ovarian response in some women, particularly those with diminished ovarian reserve. But larger, better designed studies are still needed, and no supplement, including CoQ10, has been shown to guarantee a pregnancy. It's one small, well-studied piece of a much bigger picture.

What does CoQ10 do in the body?

Short answer: CoQ10 helps your cells' mitochondria convert food into usable energy, and it also works as an antioxidant, protecting cells from damage.

Coenzyme Q10, or CoQ10, is a naturally occurring compound found in nearly every cell of your body, with the highest concentrations in organs that need the most energy: your heart, liver, kidneys, and pancreas.^[5] Its main job is inside the mitochondria, the tiny structures often called the cell's power plants, where it helps convert the food you eat into ATP, the molecule your cells actually run on.

Eggs, or oocytes, are among the most mitochondria-dense cells in the female body. A single mature egg can contain tens of thousands of mitochondria, far more than most other cell types, because the process of maturing, being fertilised, and dividing into an early embryo takes an enormous amount of energy. This is the biological reason researchers became curious about CoQ10 and fertility in the first place: if egg quality depends heavily on mitochondrial energy output, and CoQ10 is central to that process, could topping up CoQ10 levels support that system as it starts to decline?

CoQ10 also has a second role as an antioxidant, helping neutralise the oxidative stress that naturally builds up in cells over time, including in the ovaries. Your body makes its own CoQ10, and you get a small amount from foods like oily fish, organ meats, whole grains, and nuts, but dietary intake alone rarely raises levels dramatically.

To put the energy piece in context, ATP is essentially your cells' fuel currency. Every stage of an egg's development, from its earliest resting phase through to maturation, fertilisation, and the first few rounds of cell division as an embryo, runs on that fuel. If the mitochondrial machinery producing it is under-resourced, the whole process has less energy to work with at every step, not only at the final one.

Does CoQ10 decline as you get older?

Short answer: Yes. Natural CoQ10 production tends to fall with age, and this decline overlaps with the timeline of ovarian aging.

Here, the research is actually pretty clear: CoQ10 production naturally slows as we get older, and tissue levels tend to decline from around our mid-twenties onwards. It's part of the same general aging process that affects mitochondrial efficiency throughout the body, not just in the ovaries.

That timing matters for fertility. Egg quality is closely tied to mitochondrial function, and both tend to decline together as we age, which is a big part of why natural fertility gradually decreases with age and why age is one of the strongest predictors of IVF outcomes. This is not about blame or lifestyle, it's basic biology. Your ovaries are trying to do the same energy-intensive job they always have, with a cellular power supply that isn't quite what it used to be.

This overlap between the CoQ10 decline curve and the fertility decline curve is exactly what pushed researchers to start asking whether replacing some of that lost CoQ10 could help.

Can CoQ10 improve egg quality?

Short answer: Early research is promising, particularly for mitochondrial function, but "improves egg quality" is not yet a proven, guaranteed outcome in humans.

The foundational study here is a 2015 mouse study out of the University of Toronto, published in the journal Aging Cell.^[1] Researchers gave older female mice CoQ10 supplementation and found it partially restored mitochondrial function in their eggs, increased the number of eggs ovulated, and improved fertility outcomes compared with untreated older mice. It was one of the first pieces of hard evidence that CoQ10 could meaningfully affect reproductive aging, at least in animals.

Since then, researchers have studied whether the same effect shows up in women, particularly those with diminished ovarian reserve (a lower than expected number of remaining eggs for their age) undergoing IVF or ICSI. A 2024 systematic review and meta-analysis published in the journal Annals of Medicine pooled data from six randomised controlled trials and around 1,529 women with diminished ovarian reserve.^[2] CoQ10 pretreatment before an IVF cycle was associated with more eggs retrieved, fewer cancelled cycles, and a lower miscarriage rate compared with placebo or no treatment. Clinical pregnancy rates were also higher in the CoQ10 group across the pooled data.

That sounds like a clear win, and it's genuinely encouraging. But the authors were upfront about a real limitation: several of the individual trials were small, with inconsistent methods and reporting, and the authors specifically called for larger, more rigorously conducted trials before the findings can be considered settled.^[2] This is not a case of hiding the caveats. It's how honest fertility research actually reads, promising signals that haven't yet become proof.

A separate 2025 randomised controlled trial in women with poor ovarian response found a similarly mixed picture. Women who took CoQ10 before their ICSI cycle had significantly more eggs retrieved and significantly better fertilisation rates than the placebo group. But when the researchers looked at clinical pregnancy rates specifically, the difference between groups was not statistically significant.^[3] In other words, CoQ10 appeared to improve some of the biological markers along the way without necessarily translating into a measurably higher chance of a positive pregnancy test in that particular trial.

A 2025 review in Frontiers in Cell and Developmental Biology, which synthesised close to 80 studies, reached a similar conclusion: CoQ10 shows real promise for supporting mitochondrial function and reducing oxidative stress in aging eggs, with several trials showing improvements in oocyte numbers, fertilisation rates, and embryo quality, but the authors noted that clinical pregnancy and live birth data are still inconsistent across studies, and called for larger trials with standardised dosing before drawing firm conclusions.^[4]

It's also worth being clear about who most of this research has actually included. The bulk of the strongest trials are in women with diminished ovarian reserve, generally meaning lower than expected egg counts for their age, often flagged through an AMH blood test or antral follicle count. There is meaningfully less dedicated research on CoQ10 in women with PCOS, endometriosis, or unexplained fertility challenges, even though those groups make up a large share of the women actually asking about it. That gap doesn't mean CoQ10 won't help outside a diminished ovarian reserve diagnosis, but it does mean the evidence for those situations is thinner and more extrapolated than it might first appear.

So what does that actually mean for you? It means CoQ10 is a genuinely active area of fertility research, not a fringe wellness trend, and the mechanistic and early clinical evidence is more encouraging than for most supplements marketed to women trying to conceive. It also means no reputable source can honestly tell you it will improve your personal chances of conceiving. This is what I wish someone had told me the first time I went down a fertility supplement rabbit hole: promising research and proven outcomes are not the same thing, and anyone selling you certainty is selling you something the science doesn't back up yet.

How much CoQ10 should you take when trying to conceive?

Short answer: Fertility trials have typically used 200mg to 600mg daily, usually started at least one to three months before treatment.

There is no single, universally agreed dose of CoQ10 for fertility, largely because the research is still evolving and different trials have used different protocols. In the studies discussed above, daily doses generally ranged from around 200mg up to 600mg, split across one or two doses, and taken for roughly one to three months before an IVF or ICSI cycle.^[2][3]

The one-to-three-month timeframe isn't arbitrary. It roughly matches the length of time it takes for a follicle to develop from a resting stage into a mature egg, a process called folliculogenesis. If CoQ10 is going to have any meaningful effect on mitochondrial function inside a developing egg, it needs to be on board well before that egg is due to be released, not started the week before a scan.

Because CoQ10 is fat-soluble, it's typically better absorbed when taken with a meal that contains some fat rather than on an empty stomach. Beyond that, the right dose and duration for you is genuinely a conversation for your GP or fertility specialist, especially if you're already on a specific protocol with your clinic. Do not exceed the dose stated on any product label unless a healthcare professional has told you to.

Ubiquinone vs ubiquinol, does the form matter?

Short answer: Ubiquinol is the active, reduced form of CoQ10, but current research suggests formulation matters as much as which form you choose.

CoQ10 exists in two forms: ubiquinone, the oxidised form, and ubiquinol, the reduced, active form. Your body constantly converts between the two as part of its normal energy production process. Some supplement brands market ubiquinol as automatically superior because it's the "active" form and doesn't require an extra conversion step in the body, and there is some logic to that.

But a 2023 review comparing the two forms found the picture is more nuanced.^[6] The authors noted that ubiquinol is chemically unstable and has to be oxidised back to ubiquinone before it can actually be absorbed in the gut, which somewhat undercuts the "no conversion needed" marketing angle. They also found that bioavailability for both forms depends heavily on how the supplement is formulated, including the carrier oils and how finely the CoQ10 crystals are dispersed, more than on the form itself. Interestingly, the ubiquinol studies they reviewed tended to use higher doses (300 to 600mg) than the ubiquinone studies (60 to 300mg) to achieve comparable effects, which suggests ubiquinol's real-world absorption advantage may be smaller than it's often marketed to be.^[6]

Most of that comparison research has focused on cardiovascular outcomes rather than fertility specifically, since CoQ10 has a longer research history in heart health. Fertility trials have used both forms successfully. The practical takeaway is that the form (ubiquinone or ubiquinol) matters less than getting a consistent, adequately dosed product from a reputable manufacturer and taking it consistently for long enough to matter.

Is CoQ10 safe to take with other fertility supplements and medications?

Short answer: CoQ10 is generally well tolerated, but it can interact with blood thinners and diabetes medication, so check with your GP first.

According to the National Center for Complementary and Integrative Health, no serious side effects of CoQ10 have been reported in research, though some people experience mild issues like digestive upset or trouble sleeping.^[5] That said, "generally well tolerated" is not the same as "no need to mention it to anyone."

CoQ10 can interact with the blood thinner warfarin and may affect insulin or other diabetes medications, so it's important to flag any supplement, including CoQ10, to your GP or pharmacist if you're on regular medication.^[5] It's also worth telling your fertility clinic what you're taking, since they will want the full picture before and during treatment, particularly once you move into a stimulation cycle where multiple medications are being managed together.

People undergoing chemotherapy are also advised to check with their oncology team before starting CoQ10, since it may interact with how some cancer treatments work.^[5] None of this means CoQ10 is risky for most healthy women trying to conceive. It simply means "food supplement" doesn't mean "no need to mention it," and a two-minute conversation with your GP is a small price for peace of mind.

As for combining it with other fertility-focused nutrients, CoQ10 is commonly formulated alongside ingredients like myo-inositol, zinc, folate, and B vitamins in preconception supplements, and there's no established safety concern with taking them together as part of a single daily formula. Zinc contributes to normal fertility and reproduction and to normal DNA synthesis, and vitamin B6 contributes to the regulation of hormonal activity, both of which are recognised, authorised claims in the UK. Folate contributes to normal maternal tissue growth during pregnancy. Myo-inositol is one of the most studied nutrients in reproductive health, though its precise mechanisms are still an active area of research rather than a settled, proven claim.

If you're pregnant, breastfeeding, managing a diagnosed health condition, or taking any medication, always check with a healthcare professional before starting CoQ10 or any new supplement. It's not a magic fix. But it gives your body what it's often missing when diet and daily demands don't quite cover the gap.

Frequently Asked Questions

Can CoQ10 help with unexplained infertility?
There's no dedicated clinical trial showing CoQ10 resolves unexplained infertility specifically. Most of the existing research has focused on women with diminished ovarian reserve undergoing IVF, so if your situation is different, it's worth discussing with your fertility specialist rather than assuming the same results apply.

How long before I see any effect from taking CoQ10?
Because egg development takes roughly three months, most fertility research protocols use CoQ10 for at least one to three months before treatment. There's no evidence it works faster than that, and starting it the week of egg collection is unlikely to do much.

Is CoQ10 safe during pregnancy?
Safety data specifically in pregnancy and breastfeeding is limited, which is exactly why most CoQ10 fertility research stops supplementation once treatment begins or pregnancy is confirmed. Always check with your GP or midwife before continuing any supplement once you're pregnant.

Does CoQ10 help with egg quality in PCOS specifically?
Some of the broader research on CoQ10 and ovarian function includes women with PCOS, but dedicated, large-scale trials in this specific group are limited. Reviewers have called for more targeted research here rather than assuming results from diminished ovarian reserve studies transfer directly.^[4]

Should men take CoQ10 too if we're trying to conceive together?
CoQ10 has also been studied in relation to sperm quality, and it's an ingredient in MyOva's Men's Fertility Support capsules, part of our His and Hers Fertility Support Bundle. If you're trying to conceive as a couple, it's worth looking at fertility support for both partners rather than just one.

Will CoQ10 guarantee I get pregnant?
No, and be wary of anyone who tells you otherwise. No supplement, CoQ10 included, has been shown to guarantee conception. The research shows promising effects on some biological markers of egg quality, not a proven route to pregnancy.

What's the difference between taking CoQ10 alone versus in a formula like Preconception?
Taking CoQ10 alone only addresses one piece of the puzzle. A combined formula also provides nutrients with authorised UK claims, like zinc for normal fertility and reproduction and folate for normal maternal tissue growth, alongside myo-inositol, which is why many women trying to conceive prefer an all-in-one approach rather than juggling several separate bottles.

What foods naturally contain CoQ10?
Oily fish like salmon and mackerel, organ meats, whole grains, nuts, and some vegetables like broccoli and spinach all contain CoQ10, though in fairly small amounts. Diet alone typically provides only a fraction of the doses used in fertility research, which is why supplementation is usually the more practical route if you and your GP decide it's worth trying.

References

1. Ben-Meir A, Burstein E, Borrego-Alvarez A, et al. Coenzyme Q10 restores oocyte mitochondrial function and fertility during reproductive aging. Aging Cell. 2015;14(5):887-895.
2. Lin G, Li X, Lim Jin Yie S, Xu L. Clinical evidence of coenzyme Q10 pretreatment for women with diminished ovarian reserve undergoing IVF/ICSI: a systematic review and meta-analysis. Annals of Medicine. 2024;56(1):2389469.
3. Abdelrahman MA, Gamal M, Salem SA, et al. Coenzyme Q10 impact on ovarian reserve measures and the intra-cytoplasmic sperm injection (ICSI) outcomes in women with poor ovarian response: a randomized controlled study. Drug Design, Development and Therapy. 2025.
4. Jiang Y, Han Y, Qiao P, Ren F. Exploring the protective effects of coenzyme Q10 on female fertility. Frontiers in Cell and Developmental Biology. 2025;13:1633166.
5. National Center for Complementary and Integrative Health, National Institutes of Health. Coenzyme Q10. nccih.nih.gov/health/coenzyme-q10
6. Fladerer JP, Grollitsch S. Comparison of coenzyme Q10 (ubiquinone) and reduced coenzyme Q10 (ubiquinol) as supplement to prevent cardiovascular disease and reduce cardiovascular mortality. Current Cardiology Reports. 2023;25(12):1759-1767.

Further Reading

• What is PCOS? A plain-English guide
• Good habits to pick up that may help you conceive
• Preconception: our fertility support formula

This article is for general information only and does not replace advice from your GP or a qualified healthcare professional. Food supplements should not be used as a substitute for a varied and balanced diet. If you're pregnant, breastfeeding, taking medication or managing a diagnosed health condition, check with a healthcare professional before starting a new supplement.

References